Quality of life is increasingly important as a measure of chronic disease treatment outcomes. Despite growing recognition that substance abuse is a chronic disease, and the increasingly recognized negative effects on quality of life caused by the growth of nonmedical prescription drug use, quality of life is rarely measured in substance abuse treatment studies. Opioid dependence treatment is usually evaluated based on measures of abstinence. Related economic research has frequently used a cost-benefit approach that emphasizes economic offsets to treatment costs found outside of health care, such as in the legal system. There is a critical need for quality of life data in opioid dependence because of the availability of new pharmaceutical treatments (buprenorphine-naloxone and injection naltrexone). Quality of life weights are required to compare the cost- effectiveness of the new treatments to other types of care covered by private and public health insurance. This approach recognizes that the value of treatment should be appropriate to the additional cost to the health system, but need not be cost saving when compared to other medical interventions. Economic theory and standard practice require quality of life measures for cost-effectiveness analysis to take the perspective of the community, only consider physical and mental symptoms, and value opioid dependence separately from co- morbidities. In contrast, a definition that includes social welfare benefits of opioid dependence treatment and integrates patient experience of co morbidities may be more relevant and acceptable to treatment providers and policy makers. We propose to measure quality of life in opioid dependence using a community survey and secondary data collected from patients, compare outcomes with and without social welfare considerations, and develop off the shelf tools for researchers that include guidance on how to account for co-morbidities. Our specific aims are 1) to create an off the shelf list of quality o life weights for opioid dependence health states with and without social welfare considerations by developing and conducting an internet survey to directly elicit quality of life weights from a representative sample of US residents; 2) to estimate quality of life weights for patient-reported opioid dependence health states and determine the impact of social welfare considerations using data from injection and prescription opioid users enrolled in two multi-site National Drug Abuse Treatment Clinical Trials Network randomized trials, for comparison with the off the shelf weights; and 3) to assess the impact on opioid dependence quality of life weights of poorly controlled HIV and of chronic HCV using self-reported data from HIV-infected opioid dependent patients enrolled in the multi-site BHIVES cohort, and to compare these results with published algorithms for combining off the shelf weights for co-morbidities. This research is highly innovative and significant because it fills a critical gap in knowledge about quality of lif in prescription and injection opioid dependence necessary to assess economic and patient-reported outcomes, and addresses the interface between health system and social welfare perspectives.